Field of the Invention
The present disclosure relates to a wire electrical discharge machining apparatus, a wire electrical discharge machining method, and a work and a technique for decreasing the vibration of a wire due to jet flow of processing fluid supplied from a dielectric fluid supply port in a processing fluid bath to appropriately machine a workpiece by electrical discharge.
Description of the Related Art
In recent years, a method for cutting workpiece materials such as a semiconductor material, a solar cell material, and a hard material into a plurality of pieces in a short time and at the same time by the electrical discharge machining has been developed.
For example, the wire electrical discharge machining apparatus machines the workpiece material by electrical discharge such that a wire to which voltage is applied via a power feed contact is allowed to travel and the workpiece material is made close to the wire to cause an electrical discharge phenomenon, thereby slicing the workpiece material into wafers.
Japanese Patent Application Laid-Open No. 2010-260151 discusses a technique that a workpiece material is machined by electrical discharge using a plurality of travelling wires to slice the workpiece material into thin leaves.
Until now, however, as the speed of a traveling wire increases, as the number of wire electrodes increases, or as the distance between wires is decreased, for example, the traveling wire carries more processing fluid in a processing fluid bath outside the processing fluid bath, which sometimes cannot ensure a sufficient amount of the processing fluid required for wire electrical discharge machining in the processing fluid bath.
For this reason, if a sufficient amount of the processing fluid required for wire electrical discharge machining is not ensured between the workpiece (work) and a wire, which is an electrical discharge portion, atmospheric discharge, for example, occurs to break down the work being the workpiece and the wire, thereby the workpiece may not be able to be appropriately machined by the electrical discharge.
Stream of the processing fluid large in flow rate supplied to the dielectric fluid bath directly hits the wire to fluctuate the distance between wires (to vibrate the wires), whereby the workpiece may not be able to be appropriately machined by the electrical discharge. In other words, the wires are vibrated by the jet flow of the processing fluid supplied to the processing fluid bath to make it difficult to uniformly machine the workpiece.